Matrix Metalloproteinase 2 Is A Direct Target of The RAN-GTP Pathway And Mediated The Invasion, Migration And Metastasis of Human Breast Cancer Cells

Abstract Background: Ras-related nuclear protein (RAN) causses increases in invasion in vitro and is associated with early breast cancer patients deaths in vivo. However, the underlying mechanism is unknown. Methods: Effect of RAN expression on potential targets MMP2, ATF3, CXCR3 was measured by Real-Time PCR / Western blots. Effects of MMP2 and RAN expression on cancer cell lines (e.g. MDA-MB231) was mearured by soft-agar, cell adhesion, and invasion assays. Correlation between MMP2 and RAN and patient survival times was examined in breast cancer patients.Results: Knockdown of RAN lead toreduction of MMP2 and its potential regulators ATF3 and CXCR3 in breast cancer cell lines. Knockdown of ATF3 or CXCR3 downregulates MMP2 without affecting RAN, indicating that RAN regulates MMP2 through ATF3 and CXCR3. Both knockdown of RAN and MMP2 reduced cell adhesion, migration and growth in agar invasion whilst overexpression of MMP2 reversed the knockdown of RAN. Moreover, the level of immunoreactive RAN and MMP2 are positively associated with each other and with patient survival times, respectively in breast cancer specimens, suggesting that a high level of RAN may be a pre-requisite for MMP2 overexpression. Conclusions: Our results suggest that MMP2 expression can stratify progression of breast cancers with a high and low incidence of RAN and both RAN and MMP2 in combination can be used for accurate patient stratification of breast cancer metastasis.